It will now search a list of available debuggers, and try to find them
in your PATH. orterun will launch the first one that it finds.

This makes the option much more vendor-independent, and allows for
orterun to launch debuggers other than TotalView. The MCA parameter
orte_base_user_debugger can be a colon-delimited list of debuggers to
search for. It defaults to the following value (also visible via
ompi_info):

totalview @mpirun@ -a @mpirun_args@ : fx2 @mpirun@ -a @mpirun_args@

Where @mpirun@ and @mpirun_args@ are substituted at run-time. Using an
MCA parameter allows the setting of this value in all the different
ways that MCA params can be set (files, environment variables, command
line parameters).

We can certainly add in more debuggers as required; the goal is to be
inclusionary, not exclusionary.

*NOTE:* There previously was a "--debug" parameter that was a synonym
for "-d". "-d" is an OMPI-developer option to print out lots of
debugging information during the run. I hijacked --debug to now be the
user debugger option; OMPI developers can now use either -d or
--debug-devel to print out debugging information at run-time.